The Influence of Various Welding Methods on the Microstructure and Mechanical Properties of 316Ti Steel

Austenitic stainless steels are very popular due to their high strength properties, ductility, excellent corrosion resistance and work hardening. This paper presents the test results for joining AISI 316Ti austenitic steel. The technologies used for joining were the most popular welding techniques such as TIG (welding with a non-consumable electrode in the shield of inert gases), MIG (welding with a consumable electrode in the shield of inert gases) as well as high-energy EBW welding (Electron Beam Welding) and plasma PAW (plasma welding). Microstructural examinations in the face, center and root areas of the weld revealed different contents of delta ferrite with skeletal or lathy ferrite morphology. Additionally, the presence of columnar grains at the fusion line and equiaxed grains in the center of the welds was found. Microstructural, X-ray and ferroscope tests showed the presence of different delta ferrite contents depending on the technology used. The highest content of delta ferrite was found in the TIG and PAW connectors, approximately 5%, and the lowest in the EBW connector, approximately 2%. Based on the tests carried out on the mechanical properties, it was found that the highest properties were achieved by the MIG joint (R_m, 616, R_p0.2 = 335 MPa), while the lowest were achieved by the PAW joint (R_m = 576, R_p0.2 = 315 MPa).